Usher syndrome

A genetic disorder causing hearing loss and vision impairment

Usher syndrome is a rare genetic disorder that is a leading cause of combined deafness and blindness. It is characterized by sensorineural hearing loss and retinitis pigmentosa, a condition that affects vision. Usher syndrome is inherited in an autosomal recessive manner.

Classification

Usher syndrome is classified into three main types based on the severity and age of onset of symptoms:

• Type I: Individuals with Type I Usher syndrome are born profoundly deaf and experience balance problems. Vision problems typically begin in early childhood.
• Type II: Individuals with Type II have moderate to severe hearing loss from birth and normal balance. Vision problems usually begin in adolescence.
• Type III: Individuals with Type III are born with normal hearing and balance, but develop hearing and vision loss over time.

Genetics

Usher syndrome is caused by mutations in several different genes. These genes are involved in the development and function of the inner ear and retina. The condition is inherited in an autosomal recessive pattern, meaning that an individual must inherit two copies of the mutated gene, one from each parent, to be affected.

Diagram showing autosomal recessive inheritance.

Symptoms

The primary symptoms of Usher syndrome include:

• Hearing loss: Varies from moderate to profound, depending on the type.
• Vision loss: Due to retinitis pigmentosa, leading to night blindness and loss of peripheral vision.
• Balance problems: Particularly in Type I, due to vestibular dysfunction.

Diagnosis

Diagnosis of Usher syndrome involves a combination of hearing tests, vision tests, and genetic testing. Early diagnosis is crucial for managing the condition and planning for future needs.

Management

There is currently no cure for Usher syndrome, but management strategies include:

• Hearing aids or cochlear implants for hearing loss.
• Vision aids and mobility training for vision impairment.
• Genetic counseling for affected families.

Research

Research is ongoing to find better treatments and potential cures for Usher syndrome. Gene therapy and other innovative approaches are being explored.

Related pages

• Retinitis pigmentosa
• Hearing loss
• Genetic disorder